Y chromosome microdeletions, in azoospermic or near-azoospermic subjects, are located in the AZFc (DAZ) subregion

Submicroscopic deletions of the Y chromosome and polymorphisms of the androgen receptor (AR) gene in the X chromosome have been observed in men with defective spermatogenesis. To further define the subregions/genes in the Y chromosome causing male infertility and its relationship to polymorphisms of the AR polyglutamine tract, we screened the genomic DNA of 202 subfertile males and 101 healthy fertile controls of predominantly Chinese ethnic origin. Y microdeletions were examined with 16 sequence-tagged site (STS) probes, including the RBM and DAZ genes, spanning the AZFb and AZFc subregions of Yq11, and related to the size of trinucleotide repeat encoding the AR polyglutamine tract. Y microdeletions were detected and confirmed in three out of 44 (6.8%) of azoospermic and three out of 86 (3.5%) severely oligozoospermic patients. No deletions were detected in any of the patients with sperm counts of >0.5 x 10(6)/ml, nor in any of the 101 fertile controls. All six affected patients had almost contiguous Y microdeletions spanning the entire AZFc region including the DAZ gene. The AZFb region, containing the RBM1 gene, was intact in five of the six subjects. Y deletions were not found in those with long AR polyglutamine tracts. Our study, the first in a Chinese population, suggest a cause and effect relationship between Y microdeletions in the AZFc region (possibly DAZ), and azoospermia or near-azoospermia. Y microdeletions and long AR polyglutamine tracts appear to be independent contributors to male infertility.      

"Waste" follicular aspirate from fertility treatment--a potential source of human germline stem cells?

Fertility clinics worldwide routinely produce a large volume of 'waste' follicular aspirate, which is potentially an abundant source of immature ovarian follicles. Current attempts to cultivate these further in vitro to yield viable mature oocytes for fertility treatment have not yet achieved much success. Instead, recent lines of evidence have emerged that are suggestive of a potential stem cell niche within such immature ovarian follicles. The recent discovery of follicular renewal and putative germ-line stem cells within the postnatal mammalian ovary shook the foundations of reproductive biology by challenging the established dogma that mammalian females lose the capacity for germ cell renewal during fetal life, such that a fixed reserve of germ cells (oocytes) enclosed within follicles is endowed at birth. More intriguingly, another recent study in the Drosophila model provided compelling evidence that somatic progenies (nurse cells) of germ-line stem cells had the ability to revert back to the stem-cell-like state. This introduces the exciting possibility that within the mammalian ovarian follicle, similar somatic progenies of germ-line stem cells may also possess a greater intrinsic ability to revert back into functional stem cells. If this is the case, then a favored candidate would be the cumulus/granulosa of immature ovarian follicles, since such cells are true homologues of nurse cells found within the Drosophila ovary. The successful elucidation of a human germ-line stem cell niche within immature ovarian follicles is likely to have huge ramifications in stem cell biology and regenerative medicine.     

Neural progenitor cells lack immunogenicity and resist destruction as allografts

Multipotent, self-renewing stem and progenitor cells isolated from the mammalian central nervous system (CNS) have been shown to survive as allografts following transplantation to sites throughout the neuraxis. However, studies of this type shed little light upon the immunologic properties of the cells themselves, primarily because little is learned about the intrinsic immunogenic properties of a cell when it is grafted into an immune-privileged site. We have therefore investigated the immunogenic and antigenic properties of CNS progenitor cells by grafting them into a conventional (i.e., non-immune-privileged) site, namely, beneath the kidney capsule. Our results indicate that allogeneic CNS progenitor cells survive at least 4 weeks in a conventional site, during which time they neither sensitize their hosts nor express detectable levels of major histocompatibility complex (MHC) class I or II. These in vivo data are in accord with flow cytometric results showing that CNS progenitor cells do not express MHC class I or class II, either at baseline or upon differentiation in 10% serum. Exposure to interferon gamma, however, reversibly upregulates expression of these key transplantation antigens. Together, these results reveal CNS progenitor cells to possess inherent immune privilege. Since CNS progenitor cell allografts were rejected beneath the kidney capsule following specific sensitization of the host, CNS progenitor cells were able to display alloantigens, albeit not in an immunogenic form.     

Rat self administration of ethanol: Enhancement by darkness and exogenous melatonin

Using an FT 60 schedule, rats on 100% free feeding tested in the dark phase of a 12:12 light-dark cycle were trained to self-administer ethanol intravenously. The effect was dose-dependent with 20% ethanol being the preferred dose as measured by the number of infusions. Daily administration of 1.5 mg/kg melatonin significantly increased ethanol self-injection in the dark but not in the light. The time of day of testing and/or drug administration may be an important variable in studies on self-administration of drugs. Testing in the dark may eliminate the need for reducing body weight when inducing self-administration of ethanol.     

Outlining the prostate boundary using the harmonics method

In a computerised ultrasound image guidance for automated prostatectomy system, it is necessary to identify a smooth, continuous contour for the prostate (boundary) from the ultrasound image. The radial bas-relief (RBR) method, which has been reported previously, can extract a skeletonised image from an ultrasound image automatically. After this process the prostate boundary is clearly revealed. However, analysis of the image is far from complete, as there are many spurious branches that create too much ambiguity for the system to define the actual boundary. There are also sections missing from the prostate boundary. Therefore further post-processing is required to describe and define the prostate boundary. In the paper, the harmonics method is used to describe the prostate boundary. The harmonics method uses Fourier information for noise removal and encodes a smooth boundary. The results of using the harmonics method after application of the RBR method on ultrasound images are presented. Factors that affect the performance are also highlighted and discussed.     

The rise and fall of i-STAT point-of-care blood gas testing in an acute care hospital

In response to a $350,000 laboratory budget cut and closure of an intensive care unit-based laboratory and a desire to maintain turnaround times of 10 minutes or less, a multidisciplinary group developed and implemented point-of-care (POC) testing. Only blood gases (pH, PO2, and PCO2) and ionized calcium values were deemed essential stat tests. Three commercially available POC blood gas devices were evaluated; all yielded results comparable to in-house reference methods. The 1 device with a US Food and Drug Administration-approved method for ionized calcium testing and with an existing interface for laboratory information systems was selected. Fiscal analysis predicted annual savings of approximately $225,000. POC blood gas analysis was implemented in April 1996 coincident with closure of the intensive care unit-based laboratory. Clinical laboratories and POC blood gas test volumes remained constant through August 1998; in contrast, the number of ionized calcium tests decreased dramatically after April 1996. In August 1998, clinically significant (i.e., artificial ventilation parameters would have been altered based on test results) discrepant PCO2 values were observed sporadically and noted only with patient specimens, not with commercial controls or electronic simulators. Because investigation failed to identify the cause, use of the POC device was discontinued in September 1998.     

Micro-centrifugation of human spermatozoa: its effect on fertilization of hamster oocytes after micro-insemination spermatozoal transfer

Micro-centrifugation (MC) at 6500 r.p.m. (3352 g) has not beenused previously for spermatozoal concentration and subsequentfertilization. We investigated MC for micro-insemination spermatozoaltransfer (MIST) of human spermatozoa from normal donors intohamster oocytes. MC resulted in reduced penetration of hamsteroocytes, both after MIST [77.4% (41/53) versus 87.8% (43/49)for control; NS] and after exposure to zona-free hamster oocytes[60.8% (79/130) versus 72.7% (88/121) for control; P < 0.05].However, MIST under the zona resulted in better incorporationof sperm nuclei when compared with zona-free hamster oocytes,for spermatozoa exposed to micro-centrifugation (77.4 versus60.8%, P < 0.05) and controls (87.8 versus 72.7%, P <0.05). Polyspermy was higher after MIST [22.0% (9/41) versus13.9% (11/79); NS] for MC + , and [25.6% (11/43) versus 13.6%(12/88); NS] for MC-. We conclude that MC does have a negative,but minimal effect on the fertility of human spermatozoa withrespect to hamster oocytes.